strmove(): Add API, and use it instead of its pattern

[alejandro-colomar]

Cc: @kees

---

Revisions:

v1b

• Rebase

$ git rd 
1:  cc0376415cbc = 1:  2969f95a3fdc lib/string/strcpy/: memmove_T(): Add API
2:  96c06d50e92c = 2:  fc6f018d2765 lib/string/strcpy/: strmove(): Add function
3:  28aeb9f6ae4d ! 3:  b1805c7f8806 src/usermod.c: new_pw_passwd(): Use strmove() instead of its pattern
    @@ src/usermod.c
      #include "string/strdup/strdup.h"
      #include "string/strerrno.h"
      #include "string/strspn/stprspn.h"
    -@@ src/usermod.c: static char *new_pw_passwd (char *pw_pass)
    +@@ src/usermod.c: new_pw_passwd(char *pw_pass, bool process_selinux)
                              "updating-password", user_newname, user_newid, 1);
      #endif
                SYSLOG ((LOG_INFO, "unlock user '%s' password", user_newname));

v2

• Don't use a statement expression unnecessarily.

$ git rd 
1:  2969f95a3fdc ! 1:  d038ef9e46eb lib/string/strcpy/: memmove_T(): Add API
    @@ lib/string/strcpy/memmove.h (new)
     +// memmove_T - memory move type-safe
     +#define memmove_T(dst, src, n, T)   memmove_T_(dst, src, n, typeas(T))
     +#define memmove_T_(dst, src, n, T)                                    \
    -+({                                                                    \
    -+  _Generic(dst, T *: (void)0);                                  \
    -+  _Generic(src, T *: (void)0);                                  \
    -+  (T *){memmove(dst, src, (n) * sizeof(T))};                    \
    -+})
    ++(                                                                     \
    ++  _Generic(dst, T *: (void)0),                                  \
    ++  _Generic(src, T *: (void)0),                                  \
    ++  (T *){memmove(dst, src, (n) * sizeof(T))}                     \
    ++)
     +
     +
     +#endif  // include guard
2:  fc6f018d2765 = 2:  05f665578fbd lib/string/strcpy/: strmove(): Add function
3:  b1805c7f8806 = 3:  5708a7e9e1d3 src/usermod.c: new_pw_passwd(): Use strmove() instead of its pattern

v2b

• Rebase

$ git rd 
1:  d038ef9e = 1:  64fda595 lib/string/strcpy/: memmove_T(): Add API
2:  05f66557 = 2:  c9830723 lib/string/strcpy/: strmove(): Add function
3:  5708a7e9 ! 3:  9bdb78a0 src/usermod.c: new_pw_passwd(): Use strmove() instead of its pattern
    @@ src/usermod.c
     @@ src/usermod.c: new_pw_passwd(char *pw_pass, bool process_selinux)
                              "updating-password", user_newname, user_newid, 1);
      #endif
    -           SYSLOG ((LOG_INFO, "unlock user '%s' password", user_newname));
    +           SYSLOG(LOG_INFO, "unlock user '%s' password", user_newname);
     -          memmove(pw_pass, pw_pass + 1, strlen(pw_pass));
     +          strmove(pw_pass, pw_pass + 1);
        } else if (pflg) {